Lubrication of rotary expansible chamber sliding vane tool motors



' March 22, 1949. E. H. SHAFF LUBRICA'I'ION OF ROTARY EXPANSIBLE CHAMBERSLIDING VANE TOOL MOTORS 3 Sheets-Sheet 1 Filed Jan. 8, 1944 n m m fbrnes March 22, 1949.

E. H." SHAFF 2,464,997 LUBRICATION OF ROTARY EXPANSIBLE CHAMBER SLIDINGVANE TOOL MOTORS Filed Jan. 8, 1944 3 Sheets-Sheet 2 jrwerziorEggzeSiHS/zfi March 22, 1949. E; H. SHAFF 2,464,997

LUBRICATION 0F ROTARY EXPANSIBLE CHAMBER SLIDING VANE TOOL-MOTORS 3Shets-Sheet 3 Filed Jan. 8, 1944 Patented Mar. 22, 1949 UNITED STATESPATENT OFFICE LUBRICATION OF ROTARY EXPANSIBLE. CHAIVIBERI SLIDING TODLMO- TORS Ernest H.'. Shaif; Spring Lake; Michg assignorto; Keller .ToolCompany, a corporation of Micki gan Application JanuaryVS'; 1944;SerialNo: 517526 The present invention pertains toimp'rove ments inportable pneumatic .tools, and 'more' par' tic'ul-arly tov such toolsembodying rotary'type':

pneumatic motors;

One object of thepresent invention 'is to'pro vide a novel and: improvedlubricating arrangement for the cylindertwalls' of the motor of such.

a device, which'arran'gement'is ofsuch character asto insure adequateandv effective lubrication: during operation. of the motor; withoutdanger:

of floss of the lubricant twhenzthe'tool is :idle.

More:particul-arly;. it isc-anr object. to provide a: lubricating."arrangement for the" cylinderrwallsn ofithe motorofsuch: a.devicezintwhi'chzhigh ire-*- quency pressure impulses: in arestri'cted.passage leading. from a lubricant chamber to the .motor; cylinder aresetup intermittently; during opera-F tion of the tool: and: utilized: toefiectuate' the-12 Fig. 1 is afragmentarysectional viewon line I I a ofv Fig. Zlshowinga detail of construction. Fig. 2 isanexplodedperspective view-of the, tool of 1.

Fig. 3 is an explodedperspective viewot thev motor assembly for thetool.

Figs. 4 and5' are enlargedtransverse sectional.

views taken substantially along the lines. 44

and 5-5, respectively, in Fig. 1.

Fig; 61s a transverse sectional "View through the motor tak'ensubstantially along the line. 66 in Fig." 1.

Figs. 6 and'6 "are:stop motion sectional'views similar to Fig. 63

Fig. 7 is'a fragmentary detailsectional view Whilethe'= invention issusceptible of various. modifications and alternative constructions, Ihave shown in the drawings and" will herein describeindet'ail thepreferred embodiment, but:

it is tob'e'understoodthat'I do not thereby intend to limit theinvention to the specific =form'" disclosed; but intend to cover all"modifications and" alternative" constructions falling'withirrthe spiritand scope' of theinventi'on as expressed in the appended claims.

K'1hese' blades 36* are received inslots 31 which Referring moreparticularly to the exemplary embodiment of the 'invention illustratedin the" drawings, the tool there shown comprises a tool spindle 10carryinga: grinding. wheel II driven by 'a rotary type pneumatic motordesignatedi Compressed: air for operating the motoris suppliedthrou'gh'aznipple I 3 at the generally as" I2.

rear'end of the tool; thenipple servingior at-1 tachment' of a'flexible'supply :hose I4 to any suit able source .(not shown).

To house the motor. I2 and. spindle ID, a:generally.cylindrical-zcasingr orhousing' I5 is em-. ployed.Arhandle:lfiisthreaded in one end of the: casing (see-Fig. 2). asindicated at I! andtclamps; the m0tor withinthesoasing againsta'shoulder" I8 in the latter :(Figi: 1). The. opposite end: portion: I5a1'0f the casingnl 5 is1-of :reduced: diameter;

and: constitutesia' tubular spin'dlehousing. At

opposite ends. of this: spindle-housingare ball bearings. I 9 and" forsupporting the spindle l0,

thelatten'bearings also serving to support one end of the rotor'ofithemotor. The outer'race of the-ballbearing 20- is clamped-against ashoulder 2| bye-lockingring-22 threaded in the end of the casingvandhaving a packing-23 disposed between i A- needle bearing 24: within thehousing also aids in supporting they it and the bearing: races.

spindle;-

is =eccentric with respectto the axis of the cylindrical body; Theperiphery of the rotoris. cylindrical. andisdimensioned forsubstantially a line-"contact L with the inner wall of the cylinder.

bore -or chamber (see. Fig. .6) when the rotor is disposedconcentrically. with. thenbody. of the. cylinder. The endsv offthe rotorhave reduced. diameter axial'projecti'ons. 28; 29 .thereom'onebeingreceived within .a ballb'earing 30 and the, othernbeing. splin'edwithintheltelescoping inner end'ofithetool spindle I'O'and thussupported by v the bearing: I9; Retainer rings. 3|. and 32 hold takensubstantially along the 1ine"'!-I in Fig. 6; end p a es 33 and 34inposit na pp site s of the cylinder and "also support :.the bearings I9'."

and 30 which in turn support the rotor'projections 28 'and 29iD'owels35'serve'to'locatethe end plates;

The motorrotor 26 -'is provided with-aplurality of blades 36 (here shownas-three innumber) equidistantly spaced aboutthe axis of the rotorand-movable radiallyof the'latter under the compul'sion ofcentrifiigalfbrce (see Figs. 3 and 6).

extend longitudinally of the rotor and the outer edges of the bladesWipe in sealing contact with the inner wall of the cylinder. To revolvethe rotor, compressed air is admitted to the cylinder through inletports 38 located on one side of the line of contact L of the rotor withthe cylinder and permitted to escape through exhaust ports 39 located onthe opposite side of such line of contact. In the present instance theexhaust ports 39 are formed as a plurality of longitudinally spacedcircumferentially elongated slots in the cylinder, and the surroundingcasing I is longitudinally slotted as indicated at 40 (Fig. 2) so thatthe exhausting air is free to escape to atmosphere. The intake ports 38are, on the other hand, supplied with compressed air through a pair ofpassages 4l drilled in the cylinder and leading from the right-hand endthereof (as viewed in Fig. Such passages communicate with acorresponding pair of supply passages 42 formed in the handle I6 andregistering with holes 43 in the end plate 34 which in turn registerwith the ends of passages 4|.

The admission of compressed air to the supply passages 42 is controlledby a manually operable valve 44 and a governor 45 (Fig. The valve 44comprises a bushing 46 threaded in a transverse bore 41 in the handle l6and having a valve element 48 carried by a valve stem 49 slidable in it.A compression spring 50 interposed between the bottom of the bore andthe valve element normally urges the latter into closed position againstthe valve seat constituted by the inner end of the bushing. A hand lever5| pivoted on the handle l5 and overlying the end of the valve stem 49serves to thrust the latter inward for moving the valve element awayfrom its seat to open position. Compressed air is led through a passage52 from the nipple l3 to the lower end of the valve bore 41 and when thevalve element 48 is open, passes upward about it and around the reducedportion of the valve stem 49, finally emerging through openings 53 inthe bushing 46. The compressed air leaving these openings 53 passesthrough a short bore 54 into a chamber 55 from which the passages 42lead.

Entry of the compressed air into the chamber 55 is regulated by thegovernor 45 in order to maintain the speed of the motor substantiallyconstant at a value determined by the setting of the governor. As shown,the governor 45 comprises a pair of flyballs 56 pivoted on a head 51secured to the rotor extension 29 and located within a governor chamber58 in the handle "5. These fiyballs 56 have fingers 56 bearing againstthe end of a stem 59 which is slidable axially in a bushing 59 threadedin the portion of the handle separating the chambers 55 and 58 andslotted to form ports 60 controlled by the stem 59. The fiyballs act inopposition to the pressure of the air acting on the end of the valvestem exposed in the chamber 55, and tend to close the ports as the speedincreases to throttle the flow of air from the bore 54 into the chamber55 variably, depending upon the axial displacement of the stem.

Provision is made for lubricating the spindle bearings I9, 20 withlubricant, such as light grease, from a reserve supply formed by thegovernor chamber 58. For that purpose an axial passage 6| is provided inthe rotor 26 extending from end to end therethrough and communicating atits right-hand end with the interior of the governor chamber 58. Thelatter is retained under substantial pressure by compressed air leakingalong the stem 59 so that lubricant is forced from the governor chamber53 through the passage 6| to the outer end of the latter in the rotorprojection 28, the spindle housing being vented to facilitate such flowas hereinafter described. The spline coupling between the tool spindleI0 and rotor projection 28 is such as to permit lubricant to emerge fromthe latter into the spindle housing l5 through which it passes to theseveral bearings I9, 20 and 24. For that purpose, the rear end of thespindle is made in the form of a sleeve having a plurality (herein four)of longitudinal slots 62 (Fig. 5) which are of somewhat greater lengththan complemental spline teeth 63 on the rotor projection 28 (Figs. 1and 5). Since the slots thus extend somewhat beyond the end of the rotorprojection, lubricant is free to flow from the open end of the passage6| out through the unobstructed portions of these slots 32 into thespindle housing 15. The ball bearing 35 at the other or righthand end ofthe rotor 26 (Fig. 1) is lubricated directly from the governor chamber58, being mounted in one wall of the latter.

Venting of the spindle housing I5 is accomplished through a passage 14drilled in the cylinder 25 (Figs. 1 and 7) leading to a lubricant port15 which opens into the exhaust zone or portion of the cylinderalongside the exhaust ports 39. Tubes l4 pressed in the passage 14bridge the exhaust ports or slots. At its end adjacent the spindle thepassage 14 registers with a hole I6 in the end member 33, the latterhaving a radially extending relief or slot in its face adjacent thebearing l9. Since the spindle housing is thus vented through bearing l9,lubricant is carried to it and on to the port 15 where the rotor bladespick it up to wipe it around the cylinder walls.

Lubrication of the cylinder wall to prevent scoring by the rotor bladesis an especially acute problem in tools of the general type describedand, in accordance with one aspect of the present invention, a novelarrangement is provided for furnishing lubricant for that purpose andmay serve either as a supplement to or instead of the supply to thecylinder so far described. A reserve supply of lubricating oil forlubrication of the cylinder wall is contained in a chamber 76 within thehandle 16 (Fig. 1) and having a filler opening closed by a plug 16*. Inbrief, lubricant from this chamber 16 is conveyed to the cylinder byutilizing the motor rotor, when the latter is in operation, to applyintermittent high frequency impulses of pressur to an extremelyrestricted passage leading from the supply chamber to the cylinder.

In the particular construction illustrated (see Figs. 1, 4 and 6),lubricant is supplied from the chamber 16 through a small passage 11 inthe handle l6 and then through a corresponding small passage 18 in thecylinder 25 which terminates in a lubricant port 19. This latter port 19is located substantially midway between the line of contact L betweenthe rotor and cylinder and the adjacent end of the exhaust slots 39. Asthe rotor 26 revolves, each successive blade 36 passes from the positionof Fig. 6 to that of Fig. 6 and at which latter position communicationbetween the lubricant port 19 and exhaust slots 39 is cut off.Thereafter the blade and rotor compress the air trapped between theblade and the lubricant port, applying pressure to the latter. When theblade passes the lubricant port ,(Fig. 6 the "rotor. The rotor of theparticular toolillustated revolves at nearly 20,000 P. M. when runningfree and has a normal operating speed of about 12,000 R. P. M. whencontrolled by the governor 45 for normal operation. In other words,there are normally 36,000 pressure impulses per minute or 600 per secondapplied intermittently to the lubricant port i9.

To afford a suitably high degree of restriction in the passage '17, '18between the lubricant reservoir 76 and port 79, the passage is slightlyenlarged at ll (Fig. 1 and a pin Tl of only slightly smaller diameterinserted in this enlargement. By way of example, the enlarged portion ofthe passage may be 0.0960 inch in diameter and the pin 0.0937 inch indiameter. As shown, such enlarged portion is located at the junction ofthe handle with the cylinder.

It has been found that when high frequency pressure impulses are appliedto such a restricted passage in the manner described, that an efiectualand continuous flow of lubricant takes place from the supply chamber tothe lubricant port. At the latter it is picked up by the blades andwiped around the cylinder walls. On the other hand, when the tool isidle, the passage from the supply chamber is so highly restricted at Ti11 that no appreciable amount of the lubricant leaks into the cylinder.Theoretical analysis of the action of the device in inducing such flowof lubricant is difiicult. Apparently, however, the successive suddenreleases of pressure at the lubricant port cause corresponding minuteincrements of lubricant to be aspirated through it, and the nextsucceeding blade each time intercepts the increment of lubricant beforeit can be blown out of the exhaust slot and wipes it around the cylinderwall.

The intermittent pressure applied by the motor to the lubricant chamberit may also be utilized to inject lubricant into the motor cylinderthrough the port '15. For this purpose, the passage 14 (Fig. 7) isextended rearwardly from the port 15 as at M for connection with apassage 80 in the handle, leading to the chamber 16.

As previously noted, the lubricant port i opens into the inner cylinderwall on the exhaust side. When so arranged, the pulsations of pressureapplied to the port is are transmitted through the passage l8, 71 to thelubricant in the supply chamber 16, thus forcing such lubricant outthrough the passage 80 to the other lubricant port where it is picked upby successive ones of the blades 36 and wiped about the cylinder wall.The passage 80, like the passage 18, 11, must be highly restricted inorder to prevent using an excess of lubricant.

I claim as my invention:

1. In a portable tool, the combination of a rotary pneumatic motorincluding a cylinder having a rotor eccentrically mounted therein, saidrotor having a plurality of blades thereon and movable outwardlytherefrom by centrifugal action in the rotation of the rotor, saidcylinder having air inlet and exhaust ports disposed on opposite sidesof the point of least displacement of the rotor from the cylinder, saidcylinder also having a lubricant port disposed between said point andsaid exhaust port and at a lesser distance from the latter than thespacing between.

successive blades, and means defining an air tight lubricant chambercommunicating withsaid lubricant port through a highly restrictedpassage, each of said blades being operative in the rotation of therotor to trap and deliver to said chamber through said lubricant port asmall quantity of air serving to force the lubricant in the chamberreversely through the port following movement of the blade past theport.

2. In a port-able tool, the combination of a r0- tary pneumatic motorincluding a cylinder and having a cylindrical rotor eccentricallymounted therein and disposed in line contact with the.

inner wall of the cylinder, said cylinder having air inlet and exhaustports disposed on opposite sides of the line of contact between saidrotor and cylinder, said rotor having a plurality of blades thereonmovable generally radially of the same, said cylinder also having alubricant port therein disposed between said exhaust port and the lineof contact between the rotor and cylin 0 therein and disposed in linecontact with the inner wall of the cylinder, said cylinder having airinlet and exhaust ports disposed on opposite sides of the line ofcontact between said rotor and cylinder, said rotor having a pluralityof blades thereon movable generally radially of the same, said cylinderalso having first and second lubricant ports therein, said firstlubricant port being disposed between said exhaust port and the line ofcontact between the rotor and cylinder, and means defining a closedlubricant chamber communicating with said first lubricant port and alsodefining a second passage from said chamber to said second lubricantport, the latter port being located Within said cylinder in a zoneconstantly in communication with said exhaust port.

4. A portable tool having a rotary pneumatic motor including a cylinderand a rotor, said rotor having an axial projection at one end thereofprovided with longitudinally extending spline teeth, a tool spindletelescoped over said projection and having longitudinally extendingslots therein receiving said teeth, said teeth being disposed to stopshort of the inner ends of said slots to leave the inner portions of thelatter open, a bearing supporting said spindle, and said rotor having anaxially extending passage therein for supplying lubricant to saidbearing, said passage terminating at the end of said projection, wherebylubricant emerging from the passage at the end of said projection isfree to pass outward through said open inner portions of said slots intoproximity with said bearing.

5. A portable tool having a rotary pneumatic motor including a cylinderand a rotor, an elongated body providing a motor casing with extensionsat opposite ends of the motor defining, respectively, a lubricantchamber and a spindle housing, said rotor having an axial projection onthe end thereof adjacent said spindle housing, a tool spindle in saidspindle housing telescoped over said projection and splined thereto,such spline connection including longitudinal slots in said spindlereceiving teeth on said projection, bearings at opposite ends of saidspindle housing supporting said spindle, the bearing at the inner end ofsaid spindle housing receiving the end portion of the spindle telescopedover said projection and thereby also supporting the adjacent end ofsaid rotor, said rotor having an axial passage therethrough leading fromsaid lubricant chamher and terminating at a port in said projection,said teeth extending for only part of the length of said slots to permitthe egress of lubricant from said port into the spindle housing at apoint intermediate said bearings, and means for admitting air underpressure to said lubricant chamber to force lubricant from the latterthrough said passage and out of said port.

6. A portable tool having a rotary pneumatic motor including a rotor,said rotor having an axial projection at one end thereof, a tool spindlesplined to said projection, bearings for said spindle and said one endof the rotor, means defining a lubricant chamber adjacent the other endof said rotor, and said rotor having an axial passage therein leadingfrom said chamber and through said projection to a point adjacent saidbearings, said splined connection including islot permitting the escapeof lubricant from saidpassage.

ERNEST H. SHAFF.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 316,309 Telfer Apr. 21, 1885560,314 Fertig May 19, 1896 611,700 Miner Oct. 4, 1898 927,929 Bearingeret al July 13, 1909 1,122,109 Hansen Dec. 22, 1914 1,385,880 Master July26, 1921 1,514,007 Moore et al Nov. 4, 1924 1,931,167 Price et al. Oct.17, 1933 1,933,000 Young Oct. 31, 1933 2,099,280 Shafl Nov. 16, 19372,246,910 Amstberg June 24, 1941 FOREIGNPATENTS Number Country Date9,645 Great Britain Apr. 25, 1902

